We did not receive funding.

The lockdowns and restrictions associated with the COVID-19 have created a seismic shift in where work is done. Prior to the pandemic, approximately 20% of individuals were working from home while during the pandemic, more than 70% of individuals worked from home. While it is unlikely that such a large percent of the population will remain working from home, the vast support from workers for such work arrangements and the potential increase in productivity means that there will likely be a revision of the work place with more individuals working from a home office environment than have done so in the past. One unintended aspect of working from home is a reduction in light exposure, especially in the contrast between the daytime and evening. Offices converted from bedrooms, basements, and kitchens are often illuminated in the recommended 50-100 lux range, as opposed to the approximately 500 lux of most offices. While this light intensity is sufficient to work or read by, it may be insufficient to maintain adequate mental and physical health. In addition to light allowing us to consciously perceive the world around us, light can also induce a variety of changes in physiology that can impact our health, notably inducing shifts in the timing of circadian rhythms, suppressing the onset of melatonin production, and increasing alertness with subsequent changes to sleep latency and architecture. These changes in sleep and circadian rhythms have been associated with a variety of pathologies including increased risk of metabolic, psychiatric, cognitive, and cardiovascular disorders, in addition to overall longevity. Development of an adequate prophylactic countermeasure for the circadian desynchrony to which home office workers are exposed is a critical step in maintaining the health of these individuals. There are two main studies. The first study (Years 1-2) will be an in-laboratory determination of the threshold of light needed to minimize the negative impact of nocturnal light exposure. The second study (Years 3-4) will be a field study applying this threshold to determine if whether in situ use of this light intensity during the day improves health and safety among home office workers.

Current CT.gov represents the second part of this study i.e. "Study 2: The impact of daytime light intensity in home workplaces on health and well-being of remote workers. In study 2, investigators will examine a series of participants (N=36), each of whom will participate in a five-week experiment. Each participant will have a screening visit at their home. The study will be conducted over five successive one-week periods with two cohorts of participants experiencing the same series of lighting interventions. All data collection will be performed during the working days (Monday - Friday) when participants are exposed to the lighting in their home offices.

Inclusion Criteria:

• Have an occupation of a dayshift (i.e., occurring between 6 AM and 8 PM) remote office worker, working from home for five days (Monday→Friday) a week with a maximum of 12 hours per day.
• Aged 18-65
• Good health [self-reported medical history]
• Female or male
• No evidence of sleep disorders [PSQI scores >5 are excluded]
• No extreme chronotypes (extreme owl or lark) [reduced MEQ scores >27 or <11 are excluded; typical bedtime between 8 PM and 2 AM]
• Non-smoker
• Not abusing alcohol [AUDIT scores >19 are excluded]
• Not experiencing depression [CES-D scores >27 are excluded]
• Best-corrected visual acuity of 20/200 or higher
• Normal color vision [as per Ishihara's Tests for Colour Deficiency]
• No current or planned use of light therapy or light-altering devices (e.g., blue-blocking and/or tinted glasses and contact lenses)
• No planned upcoming travel during the study participation period
• Not pregnant

Exclusion Criteria:

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